Re: [PATCH v5 35/38] mm: avoid use of VMA_SPECIAL_FLAGS in migrate_vma_setup()

On Mon, Oct 12, 2026 at 08:52:07PM +0200, David Hildenbrand (Arm) wrote:

On 10/9/26 20:04, Lorenzo Stoakes (ARM) wrote:

quoted

diff --git a/mm/migrate_device.c b/mm/migrate_device.c
index b9c453c28795..289d7b08ace4 100644
--- a/mm/migrate_device.c
+++ b/mm/migrate_device.c

quoted

 int migrate_vma_setup(struct migrate_vma *args)
 {
+	const struct vm_area_struct *vma = args->vma;
 	long nr_pages = (args->end - args->start) >> PAGE_SHIFT;

 	args->start &= PAGE_MASK;
 	args->end &= PAGE_MASK;
-	if (!args->vma || vma_test_any_mask(args->vma, VMA_SPECIAL_FLAGS) ||
-	    vma_is_dax(args->vma))
+	if (!vma)
+		return -EINVAL;
+	if (!vma_is_mm_managed(vma) || vma_is_fixed_mapping(vma) ||
+	    vma_is_dax(vma))

Same here, with the droppable thing changed this would be

!vma_is_mm_backed() || vma_is_dax(vma)

I guess.

I think we need a hugetlb carveout too (ugh), will update in v6!

Acked-by: David Hildenbrand (Arm) <david@kernel.org>

Thanks!

--
Cheers, Lorenzo